U.S. patent number 7,785,733 [Application Number 10/803,565] was granted by the patent office on 2010-08-31 for reserve cell-array nanostructured battery.
This patent grant is currently assigned to Alcatel-Lucent USA Inc.. Invention is credited to Marc Scott Hodes, Paul Robert Kolodner, Thomas Nikita Krupenkin, Alan Michael Lyons, Mary Louise Mandich, Joseph Ashley Taylor, Donald Weiss.
United States Patent |
7,785,733 |
Hodes , et al. |
August 31, 2010 |
Reserve cell-array nanostructured battery
Abstract
A battery having an electrode with at least one nanostructured
surface is disclosed wherein the nanostructured surface is divided
into cells and is disposed in a way such that an electrolyte fluid
of the battery is prevented from contacting the portion of
electrode associated with each cell. When a voltage is passed over
the nanostructured surface associated with a particular cell, the
electrolyte fluid is caused to penetrate the nanostructured surface
of that cell and to contact the electrode, thus activating the
portion of the battery associated with that cell. The
current/voltage generated by the battery is controlled by
selectively activating only a portion of the cells. Multiple cells
can be active simultaneously to produce the desired voltage. The
more cells that are active, the higher the current/voltage and the
lower the overall life of the battery. The life of the battery can
be extended by activating fewer cells simultaneously.
Inventors: |
Hodes; Marc Scott (Somerville,
MA), Kolodner; Paul Robert (Hoboken, NJ), Krupenkin;
Thomas Nikita (Middletown, WI), Lyons; Alan Michael (New
Providence, NJ), Mandich; Mary Louise (Martinsville, NJ),
Taylor; Joseph Ashley (Madison, WI), Weiss; Donald
(Cresskill, NJ) |
Assignee: |
Alcatel-Lucent USA Inc. (Murray
Hill, NJ)
|
Family
ID: |
42337200 |
Appl.
No.: |
10/803,565 |
Filed: |
March 18, 2004 |
Prior Publication Data
|
|
|
|
Document
Identifier |
Publication Date |
|
US 20100183906 A1 |
Jul 22, 2010 |
|
Related U.S. Patent Documents
|
|
|
|
|
|
|
Application
Number |
Filing Date |
Patent Number |
Issue Date |
|
|
10716084 |
Jun 5, 2007 |
7227235 |
|
|
|
Current U.S.
Class: |
429/112; 429/118;
977/948; 429/62 |
Current CPC
Class: |
H01M
4/06 (20130101); H01M 6/32 (20130101); H01M
6/36 (20130101); F42C 19/00 (20130101); H01M
6/30 (20130101); Y10S 977/948 (20130101) |
Current International
Class: |
H01M
10/50 (20060101) |
References Cited
[Referenced By]
U.S. Patent Documents
Other References
Kim, et al., "Nanostructured Surfaces for Dramatic Reduction of
Flow Resistance in Droplet-Based Microfluidics," IEEE, pp. 479-482
(2002). cited by other.
|
Primary Examiner: Maples; John S
Attorney, Agent or Firm: Hitt Gaines, PC
Parent Case Text
CROSS REFERENCE TO RELATED APPLICATIONS
This application is a continuation-in-part of U.S. Ser. No.
10/716,084, filed 18 Nov. 2003, now U.S. Pat. No. 7,227,235.
This application claims subject matter that is described in
co-pending United States Patent Application filed simultaneously
herewith and entitled "Nanostructured Battery Having End-Of-Life
Cells," Ser. No. 10/803,576 filed on Mar. 18, 2004 and United
States Patent Application filed simultaneously herewith and
entitled "Reversibly-Activated Nanostructured Battery," Ser. No.
10/803,641 filed on Mar. 18, 2004.
Claims
What is claimed is:
1. An apparatus comprising: a first electrode having a plurality of
separate cells; an electrolyte fluid; a nanostructured surface
corresponding to at least one of said cells in said plurality of
separate cells, wherein said nanostructured surface is disposed
between a portion of said electrode in said at least one of said
cells and said electrolyte fluid in a way such that said
nanostructured surface prevents contact of the electrolyte fluid
and said portion of said electrode.
2. The apparatus of claim 1 further comprising: means for causing
said electrolyte fluid to penetrate at least a portion of said
nanostructured surface corresponding to at least one of said cells
in said plurality of separate cells in a way such that said
electrolyte contacts said electrode.
3. The apparatus of claim 2 wherein said means for causing
comprises means for generating a voltage across said at least a
portion of said nanostructured surface.
4. The apparatus of claim 2 wherein said means for causing
comprises means for increasing the temperature of said
nanostructured surface.
5. The apparatus of claim 2 wherein said at least one of said cells
comprises those cells whereby, upon permitting said electrolyte to
penetrate the nanostructures corresponding to said cells, a
predetermined voltage is generated by said apparatus.
6. The apparatus of claim 1 further comprising: a voltage generator
for applying a voltage to at least a portion of said nanostructured
surface in a way such that the angle of contact of said electrolyte
with at least a portion of the nanostructures on said
nanostructured surface changes.
7. A battery comprising: a plurality of electrodes; a plurality of
nanostructures disposed on a surface of at least one of said
electrodes, said surface divided into a plurality of separate
cells, wherein said electrodes are disposed between an electrolyte
fluid and that portion of said surface corresponding to each of
said plurality of separate cells; and means for applying a voltage
to said nanostructures, said voltage operative to decrease the
angle of contact between said electrolyte and said nanostructures,
thereby causing said electrolyte fluid to penetrate said
nanostructures and contact said surface.
Description
FIELD OF THE INVENTION
The present invention relates generally to batteries and, more
particularly, to batteries having nanostructured surfaces.
BACKGROUND OF THE INVENTION
Many beneficial devices or structures in myriad applications rely
on batteries as a power source. A typical liquid-cell battery, such
as battery 101 in FIG. 1, is characterized by an electrolyte liquid
102 which provides a mechanism for an electrical charge to flow in
direction 103 between a positive electrode 104 and a negative
electrode 105. When such a battery 101 is inserted into an
electrical circuit 106 with illustrative load 108, it completes a
loop which allows electrons to flow in direction 107 around the
circuit 106. The positive electrode thus receives electrons from
the external circuit 106. These electrons then react with the
materials of the positive electrode 104 in reduction reactions that
generate the flow of a charge to the negative electrode 105 via
ions in the electrolyte liquid 102. At the negative electrode 105,
oxidation reactions between the materials of the negative electrode
104 and the charge flowing through the electrolyte fluid 102 result
in surplus electrons that are released to the external circuit
106.
As the above process continues, the active materials of the
positive and negative electrodes 104 and 105, respectively,
eventually become depleted and the reactions slow down until the
battery is no longer capable of supplying electrons. At this point
the battery is discharged. It is well known that, even when a
liquid-cell battery is not inserted into an electrical circuit,
there is often a low-level reaction with the electrodes 104 and 105
that can eventually deplete the material of the electrodes. Thus, a
battery can become depleted over a period of time even when it is
not in active use in an electrical circuit. This period of time
will vary depending on the electrolyte fluid used and the materials
of the electrodes.
More recently, batteries having at least one nanostructured surface
have been proposed wherein nanostructures are used to separate the
electrolyte from the electrode until such a time that the battery
is to be used. An example of the use of electrowetting principles
applied to batteries is described in copending U.S. patent
application Ser. No. 10/716,084 filed Nov. 18, 2003 and entitled
"Electrowetting Battery Having Nanostructured Surface," which is
hereby incorporated by reference herein in its entirety. As
disclosed in the '084 application, when it is desired that the
battery generate a charge, the electrolyte is caused to penetrate
the nanostructured surface and to come into contact with the
electrode of the battery, thus resulting in the above-discussed
flow of electrons around a circuit. Such a penetration of
nanostructures is achieved, for example, by applying a voltage to
the nanostructures such that the contact angle of the electrolyte
relative to the nanostructured surface is decreased. When the
contact angle is decreased, the electrolyte penetrates the
nanostructures and is brought into contact with the electrode.
SUMMARY OF THE INVENTION
The present inventors have realized that it would be advantageous
to be able to selectively control the voltage and/or current of a
battery and to variably control the operational life of such a
battery.
Therefore, the present inventors have invented a battery having an
electrode with at least one nanostructured surface. The
nanostructured surface is divided into cells and is disposed in a
way such that an electrolyte fluid of the battery is prevented from
contacting the portion of electrode associated with each cell. When
a voltage is applied to the nanostructured surface associated with
a particular cell, the electrolyte fluid is caused to penetrate the
nanostructured surface of that cell and to contact the electrode,
thus activating the portion of the battery associated with that
cell. Thus, when the activated battery is inserted into an
electrical circuit, electrons will flow along the circuit.
The voltage generated by the battery is controlled by selectively
activating only a portion of the cells. Multiple cells can be
active simultaneously to produce the desired voltage and/or
current. The more cells that are active, the higher the voltage
and/or current and the lower the overall life of the battery. The
life of the battery can be extended by activating fewer cells
simultaneously.
BRIEF DESCRIPTION OF THE DRAWING
FIG. 1 shows a prior art liquid-cell battery as used in an
electrical circuit;
FIG. 2 shows a prior art nanopost surface;
FIGS. 3A, 3B, 3C, 3D and 3E show various prior art nanostructure
feature patterns of predefined nanostructures that are suitable for
use in the present invention;
FIG. 4 shows a more detailed view of the prior art nanostructure
feature pattern of FIG. 3C;
FIGS. 5A and 5B show a device in accordance with the principles of
the present invention whereby electrowetting principles are used to
cause a liquid droplet to penetrate a nanostructure feature
pattern;
FIG. 6 shows the detail of an illustrative nanopost of the
nanostructure feature pattern of FIGS. 5A and 5B;
FIG. 7 shows an illustrative liquid-cell battery in accordance with
the principles of the present invention wherein the electrolyte in
the battery is separated from the negative electrode by
nanostructures;
FIG. 8 shows the illustrative battery of FIG. 7 wherein the
electrolyte in the battery is caused to penetrate the
nanostructures and to thus contact the negative electrode; and
FIG. 9 shows an illustrative array of cells useful in accordance
with the principles of the present invention.
DETAILED DESCRIPTION
FIG. 2 shows an illustrative nanopost pattern 201 with each
nanopost 209 having a diameter of less than 1 micrometer. While
FIG. 2 shows nanoposts 209 formed in a somewhat conical shape,
other shapes and sizes are also achievable. In fact, cylindrical
nanopost arrays have been produced with each nanopost having a
diameter of less than 10 nm. Specifically, FIGS. 3A-3E show
different illustrative arrangements of nanoposts produced using
various methods and further show that such various diameter
nanoposts can be fashioned with different degrees of regularity.
Moreover, these figures show that it is possible to produce
nanoposts having various diameters separated by various distances.
An illustrative method of producing nanoposts, found in U.S. Pat.
No. 6,185,961, titled "Nanopost arrays and process for making
same," issued Feb. 13, 2001 to Tonucci, et al, is hereby
incorporated by reference herein in its entirety. Nanoposts, as
well as other shapes of nanostructures, have been manufactured by
various methods, such as by using a template to form the posts, by
various means of lithography, and by various methods of
etching.
FIG. 4 shows the illustrative known surface 401 of FIG. 3C with a
nanostructure feature pattern of nanoposts 402 disposed on a
substrate. Throughout the description herein, one skilled in the
art will recognize that the same principles applied to the use of
nanoposts or nanostructures can be equally applied to microposts or
other larger features in a feature pattern. The surface 401 and the
nanoposts 402 of FIG. 4 are, illustratively, made from silicon. The
nanoposts 402 of FIG. 4 are illustratively approximately 350 nm in
diameter, approximately 6 .mu.m high and are spaced approximately 4
.mu.m apart, center to center. It will be obvious to one skilled in
the art that such arrays may be produced with regular spacing or,
alternatively, with irregular spacing.
As typically defined a "nanostructure" is a predefined structure
having at least one dimension of less than one micrometer and a
"microstructure" is a predefined structure having at least one
dimension of less than one millimeter. However, although the
disclosed embodiments refer to nanostructures and nanostructured
surfaces, it is intended by the present inventors, and will be
clear to those skilled in the art, that microstructures may be
substituted in many cases. Accordingly, the present inventors
hereby define nanostructures to include both structures that have
at least one dimension of less than one micrometer as well as those
structures having at least one dimension less than one millimeter.
The term "feature pattern" refers to either a pattern of
microstructures or a pattern of nanostructures. Further, the terms
"liquid," "droplet," and "liquid droplet" are used herein
interchangeably. Each of those terms refers to a liquid or a
portion of liquid, whether in droplet form or not.
The present inventors have recognized that it is desirable to be
able to control the penetration of a given liquid into a given
nanostructured or microstructured surface and, thus, control the
contact of the liquid with the underlying substrate supporting the
nanostructures or microstructures. FIGS. 5A and 5B show one
embodiment where electrowetting is used to control the penetration
of a liquid into a nanostructured surface. Electrowetting
principles and controlling the movement of a liquid across a
nanostructured or microstructured surface are generally described
in U.S. patent application Ser. No. 10/403,159 filed Mar. 31, 2003
and titled "Method And Apparatus For Variably Controlling The
Movement Of A Liquid On A Nanostructured Surface," which is hereby
incorporated by reference herein in its entirety. As discussed
previously, the general use of electrowetting principles in
batteries is described in above-referenced copending U.S. patent
application Ser. No. 10/716,084. One skilled in the art will
recognize that a variety of shapes of structures, such as microline
structures, are equally useful in accordance with the principles of
the present invention and, indeed, may be preferably used in place
of nanoposts. Microlines and other suitable structures are more
fully discussed in the '159 application referenced herein above.
Referring to FIG. 5A, a droplet 501 of conducting liquid (such as
an electrolyte solution in a liquid-cell battery) is disposed on
nanostructure feature pattern of cylindrical nanoposts 502, as
described above, such that the surface tension of the droplet 501
results in the droplet being suspended on the upper portion of the
nanoposts 502. In this arrangement, the droplet only covers surface
area f.sub.1 of each nanopost. The nanoposts 502 are supported by
the surface of a conducting substrate 503. Droplet 501 is
illustratively electrically connected to substrate 503 via lead 504
having voltage source 505. An illustrative nanopost is shown in
greater detail in FIG. 6. In that figure, nanopost 502 is
electrically insulated from the liquid (501 in FIG. 5A) by material
601, such as an insulating layer of dielectric material. The
nanopost is further separated from the liquid by a low surface
energy material 602, such as a well-known fluoro-polymer. Such a
low surface energy material allows one to obtain an appropriate
initial contact angle between the liquid and the surface of the
nanopost. It will be obvious to one skilled in the art that,
instead of using two separate layers of different material, a
single layer of material that possesses sufficiently low surface
energy and sufficiently high insulating properties could be
used.
FIG. 5B shows that, by applying a low voltage (e.g., 10-20 volts)
to the conducting droplet of liquid 501, a voltage difference
results between the liquid 501 and the nanoposts 502. The contact
angle between the liquid and the surface of the nanopost decreases
and, at a sufficiently low contact angle, the droplet 501 moves
down in the y-direction along the surface of the nanoposts 502 and
penetrates the nanostructure feature pattern until it complete
surrounds each of the nanoposts 502 and Comes into contact with the
upper surface of substrate 503. In this configuration, the droplet
covers surface area f.sub.2 of each nanopost. Since
f.sub.2>>f.sub.1, the overall contact area between the
droplet 501 and the nanoposts 502 is relatively high such that the
droplet 501 contacts the substrate 503. One skilled in the art will
recognize that other methods of causing the electrolyte to
penetrate the nanostructures, such as decreasing the temperature of
the electrodes, can be used. The present invention is intended to
encompass any such method of causing such penetration.
FIG. 7 shows an illustrative battery 701 whereby an electrolyte
fluid 702 is contained within a housing having containment walls
703. The electrolyte fluid 702 is in contact with positive
electrode 704, but is separated from negative electrode 708 by
nanostructured surface 707. Nanostructured surface 707 may be the
surface of the negative electrode or, alternatively, may be a
surface bonded to the negative electrode. One skilled in the art
will recognize that the nanostructured surface could also be used
in association with the positive electrode with similarly
advantageous results. In FIG. 7, the electrolyte fluid is suspended
on the tops of the nanoposts of the surface, similar to the droplet
of FIG. 5A. The battery 701 is inserted, for example, into
electrical circuit 705 having load 706. When the electrolyte liquid
is not in contact with the negative electrode, there is
substantially no reaction between the electrolyte and the
electrodes 704 and 705 of the battery 701 and, therefore, there is
no depletion of the materials of the electrodes. Thus, it is
possible to store the battery 701 for relatively long periods of
time without the battery becoming discharged.
FIG. 8 shows the battery 701 of FIG. 7 inserted into electrical
circuit 705 wherein, utilizing the electrowetting principles
described above, a voltage is applied to the nanostructured surface
707, thus causing the electrolyte fluid 702 to penetrate the
surface 707 and to come into contact with the negative electrode
708. One skilled in the art will recognize that this voltage can be
generated from any number of sources such as, for example, by
passing one or more pulses of RF energy through the battery. When
the penetration of the electrolyte into the nanostructures occurs,
electrons begin flowing in direction 801 through the circuit 705,
as described above, and the load 706 is powered. Thus, the
embodiment of FIGS. 7 and 8 show how a battery can be stored
without depletion for a relatively long period of time and can then
be "turned on" at a desired point in time to power one or more
electrical loads in an electrical circuit.
FIG. 9 shows one illustrative embodiment of a novel battery, such
as a lithium-ion or lead-acid battery, in accordance with the
principles of present invention. In FIG. 9, battery 900 has
positive electrode 901 and negative electrode 907 which are,
illustratively, parallel plate electrodes. Leads 901a and 907a are,
for example, electrically conductive leads useful for connecting
the battery to an electrical load. Electrolyte 906, which is any
one of well-known electrolytes suitable for use in battery 900, is
contained within a cavity separating electrodes 901 and 907. Each
of the electrodes 901 and 907 has at least one surface that is
exposed to the electrolyte in a way such that, when active, an
electrical current is generated by the battery, due to the
reactions between the electrolyte and electrodes, as described
previously. The portion of the surface of electrode 901 that is
exposed to the electrolyte is illustratively a nanostructured
surface, similar to the nanostructured electrode 707 in FIG. 7. One
skilled in the art will recognize that portions of both electrode
901 and electrode 907 may be nanostructured similar to electrode
707.
The illustrative battery 900 of FIG. 9 functions in similar fashion
to the battery 701 of FIG. 7. However, the present inventors have
recognized that it would be desirable to have greater control over
the current and/or voltage produced by the battery, as well as
better control over the life of the battery. Therefore, in order to
achieve this control, nanostructured electrode 901 the present
inventors have divided the electrode into an array of cells, or
pixels. The array of cells is arranged in columns and rows, such
as, illustratively, columns 909 of cells and rows 910 of cells. By
allowing the electrolyte to penetrate only one or more particular
cells in the array, for example by only applying a low voltage to
the nanostructures in those cells, the current/voltage produced by
the battery 900 can be selected at a particular desired level
depending on the application.
In one potential embodiment of a selective and variable current
application, battery 900 of FIG. 9 is inserted into an illustrative
electrical circuit 911 having illustrative electrical load 913. In
this illustrative example, four cells 903 on the positive electrode
are currently active or, in other words, are producing a flow of
ions from the positive electrode 901 to the negative electrode 907
and thus producing an electrical current flowing in direction 912
over the electrical circuit from lead 907a to lead 901a. Power is
thus provided to load 913. One skilled in the art will recognize
that, by using fewer cells, a reduced flow of ions between
electrodes 901 and 907 result, thus reducing the current produced
by the battery 900. In this case, however, the theoretical life of
the battery will be longer since a smaller area of electrode 901 is
in contact with the electrolyte in a given amount of time. On the
other hand, it is possible to activate all cells in the array at
one time, which provides the theoretical potential of producing a
relatively high instantaneous current. However, one skilled in the
art will recognize that battery life will be greatly reduced since
the entire surface area of the electrode corresponding to all the
activated cells will be depleted more quickly.
The foregoing embodiment describes a battery where the current
generated by the battery is capable of being varied. One skilled in
the art will recognize that this is possible when the electrolyte
is disposed in an open chamber between the electrodes in a way such
that the electrolyte is common among all the cells. The plurality
of cells formed on the electrode(s) are electrically connected in
parallel and, therefore, the current of the battery can be varied
by activating one or more cells. The more cells that are activated,
the greater the current generated by the battery.
The present inventors have realized that, in addition to variably
controlling the current produced by the battery, it may be
desirable to also variably control the voltage of a battery. One
skilled in the art will recognize that varying the number of cells
connected in series could achieve such a variable control of
voltage. Thus, in order to achieve such a series connection, the
present inventors have invented a battery wherein, instead of
disposing the electrolyte in an open chamber, the area below each
cell between electrodes 901 and 907 is separated from the other
cells. Thus, multiple individually electrically isolated
compartments are associated with each of the cells on electrode 901
so that, when the number of activated cells is varied, the voltage
of the battery is correspondingly varied. Accordingly, in this
case, activating more cells leads to a higher voltage produced by
the battery. One skilled in the art will fully appreciate that, by
implementing the appropriate standard electronic circuitry in, for
example, the battery control circuit, the battery can be
dynamically switched between a series and a parallel connection,
thus selectively permitting variable control of the circuit or the
voltage of the battery. In many applications, it may be desirable
to activate only a portion of cells, such as cells 903, in normal
operations and then, in cases where emergency power is require or
when any other unusual demand is realized, to active additional
cells as needed. In normal operations, the current/voltage supplied
to the circuit can be maintained by progressively activating new
cells when old cells become depleted. For example, cells 902
represent those cells that have already been depleted and, as
discussed, cells 903 represent those cells that are currently
active. Cells 904 represent those cells that have not been
activated. In this illustrative example, one possible progression
of cells is that, as the individual cells in column 914 are
depleted, cells in column 915 are progressively activated in
direction 908, followed by activation of the cells in column 916,
followed by column 917 and then column 918 until the final cell 905
is activated. One skilled in the art will recognize that many paths
or selection methods for selecting cells to be activated may be
used to achieve a desired voltage/current level and/or battery
life, including random activation. The principles of the present
invention are contemplated to include any and all such methods. One
skilled in the art will also recognize that, in addition to
dividing electrode 901 into cells, electrode 907 could likewise be
divided into cells. If those divided cells of electrode 907 are
nanostructured as discussed above, one or more cells in electrode
907 may be selectively activated at the same time a corresponding
cell on electrode 901 is activated, thus providing a discrete flow
of ions between one particular cell on electrode 901 and one
particular cell on electrode 907. Alternatively, the electrolyte
may be permitted to contact the entire area of one of electrodes
901 and 907, but may only be permitted to contact selected
activated cells on the other electrode. One skilled in the art will
recognize, in light of the teachings herein, that many such
arrangements are possible and that such arrangements are fully
contemplated by the principles of the present invention.
The foregoing merely illustrates the principles of the invention.
It will thus be appreciated that those skilled in the art will be
able to devise various arrangements which, although not explicitly
described or shown herein, embody the principles of the invention
and are within its spirit and scope. For example, one skilled in
the art, in light of the descriptions of the various embodiments
herein, will recognize that the principles of the present invention
may be utilized in widely disparate fields and applications. For
example, while the embodiment disclosed herein is a battery having
nanostructured surfaces, one skilled in the art will appreciate
that such nanostructured surfaces may be used for other uses, such
as in use as a thermostat. In such a case, the characteristics of
the pattern of nanostructures and the liquid in contact with the
nanostructures can be chosen in a way such that, upon a temperature
increase of known amount, the liquid will penetrate the surface,
thus achieving a desired result. One skilled in the art will be
able to devise many similar uses of the underlying principles
associated with the present invention, all of which are intended to
be encompassed herein. All examples and conditional language
recited herein are intended expressly to be only for pedagogical
purposes to aid the reader in understanding the principles of the
invention and are to be construed as being without limitation to
such specifically recited examples and conditions. Moreover, all
statements herein reciting aspects and embodiments of the
invention, as well as specific examples thereof, are intended to
encompass functional equivalents thereof.
* * * * *